CA2009034C - Telephone or data switching system with variable protocol inter-office communication - Google Patents

Abstract

A method of producing interoffice signalling comprising storing program blocks for commanding generation, in a plurality of signalling protocols, of signalling signals in a communication switching system, storing correlations of particular ones of the program blocks with a particular protocol for signalling functions related to the process of a call to or from the communication switching system, enabling operation of the particular ones of the program blocks when a particular signalling signal is to be generated in the processing of a telephone call to or from the communication switching system, to match the particular protocol, whereby the communication switching system is enabled to process calls restricted to the particular protocol out of the plurality of protocols for a particular call.

Description

2~09034 02 This invention relates to a telephone or 03 data signal switching system and particularly to one 04 which contains an adaptable protocol facility to 05 provide different variants of an inter-office 06 signalling protocol, such as R2 signalling, and to a 07 method of providing the protocol.
08 R2 signalling is a form of inter-switching 09 office signalling which has been standardized by CCITT. This type of signalling uses dual tone 11 multi-frequency (MF) signals, and is referred to as 12 "compelled". In R2 signalling, an outgoing register 13 of an originating switching office sends a first 14 forward MF inter-register signal which is detected and recognized at a receiving office, which can be at the 16 far end of a sequence of tandem switching offices.
17 Upon recognizing the first forward inter-register 18 signal, the receiving office sends a backward 19 inter-register MF signal to the originating office, which has its own meaning and at the same time serves 21 as an acknowledgment. This backward inter-register 22 signal is detected and recognized at the originating 23 office whereupon it sends the next forward 24 inter-register signal to the receiving office. Again the receiving office sends a next backward 26 inter-register signal to the originating office, and 27 the back and forth communication continues until the 28 last inter-register signal has been sent. The 29 communication between switching offices is conducted between an outgoing register of the originating 31 central office, via a trunk, to a similar incoming 32 register at the receiving central office.
33 The system of communication is referred to 34 as "compelled" because the oriqinating switching office transmits signals in response to backward 36 signals provided by the receiving switching office.
37 The compelled nature of the protocol gives the R2 form 38 of signalling significant flexibility. This includes 02 not only the ability to transmit a variety of 03 information, such as address signals, congestion 04 signals, calling and called party status signals, 05 etc., but also the ability to work end-to-end.
06 End-to-end signalling is the ability to communicate 07 directly with a far end incoming register, even if 08 several intervening central offices have been used to 09 route the call.
While the CCITT standard is usually used 11 between international switching exchanges, numerous 12 variants have been created for national use. Some of 13 those variants have little in common with the CCITT R2 14 protocol except for the signalling frequencies used.
The fact that various variants of the 16 standard have been implemented by various countries 17 has resulted in local national switching offices that 18 must be provided uniquely programmed to implement the 19 local national protocol. Since most modern switching offices are program controlled, should changes be 21 required to the switching office due to a change in 22 national protocol or due to the switch being moved, 23 etc., new switching office computer programs are 24 required to be resident in the switching office.
Typically, these programs are supplied on EPROM, 26 floppy disk or magnetic tape and are supplied in each 27 instance by the switching system supplier which is 28 totally familiar with the programming requirements of 29 its switching system product.
Changing or updating of a switching office 31 due to a change in the inter-office communications 32 protocol requires, however, significant programming 33 effort on at least a country by country and switching 34 system by switching system basis, which is costly to the customer and time consuming for the supplier.
36 In addition, with the expansion of world 37 trade in switching systems, it is desirable for a 38 switching system supplier to be able to provide a 01 _ 3 _ 02 single switching system that can be easily adapted to 03 provide and receive a large variety of inter-office 04 signalling protocols or all variants of a standard 05 signalling protocol at minimum cost. Until the 06 present invention, this has not been achievable at a 07 significantly low cost and with as much ease as is 08 possible using the present invention.
09 In the present invention there is stored at each switching office a plurality of program 11 procedures, referred to herein as program building 12 blocks, for implementing different portions of a 13 variety of signalling protocols for a signalling 14 standard that is to be used, such as R2. In other words, small specialized control programs for 16 controlling the signalling signal to be transmitted, 17 which can be used to control the form of every 18 different possible siqnal that is to be transmitted, 19 are stored at the switching office. After installation of the switching office, the customer, by 21 means of an user interface which is easy to use (e.g.
22 by means of a form displayed on a terminal screen), 23 selects the form of signal for each kind of signal to 24 be transmitted using the local national protocol. The switching office personnel (or customer) thereby 26 designate the corresponding program building blocks.
27 The designating codes are downloaded to the control 28 memories of the portions of the switching office that 29 are to control the signalling protocol. Once downloaded and resident, the switching office uses 31 corresponding building block control procedures 32 designated by the desiqnating codes in the control 33 memories to control the form of the signalling into 34 the desiqnated protocol.
A similar function is provided for 36 controlling the reception of, and interpretation of 37 signals received from the distant office in the same 38 protocol, from the trunk.

_ 4 _ 2009034 2 As a result the switching office manufacturer

3 is no longer obligated to customize the switching system

4 inter-office signalling for each national market. The S customer himself designates the signalling signals 6 required to implement the protocol, and the resulting 7 corresponding program procedures which are already 8 resident in the machine automatically modify the 9 switching office to cause the signalling protocol to be implemented. This provides great flexibility and saves 11 considerable time and money on the part of the customer 12 upon initial installation of the switching system and 13 with a requirement to change the signalling protocol.
14 The result is a more easy to install and implement switching office which provides reduced cost to 16 the customer, increased flexibility, a saving in manpower 17 for the switching system supplier, and an universal 18 switching office that can be sold for use in all markets 19 which use variants of the same standard signalling protocol: in the case of CCITT R2 signalling, this 21 includes most countries of the world.
22 One embodiment of the invention is a method of 23 producing interoffice signalling comprising storing 24 program building blocks for commanding generation, in a plurality of signalling protocols of signalling signals 26 in a communication switching system, storing correlations 27 of particular ones of the program building blocks with a 28 particular protocol for signalling functions related to 29 the process of a call to or from the communication switching system, enabling operation of the particular 31 ones of the program building blocks when a particular 32 signalling signal is to be generated in the processing of 33 a telephone call to or from the communication switching 34 system, to match the particular protocol, whereby the communication switching system is enabled to process 36 calls restricted to the particular protocol out of the 1 _ 5 _ 2009034 2 plurality of protocols for a particular call.
3 - Another embodiment of the invention is a 4 communication switching system comprising signal S generating apparatus for generating interoffice 6 signalling signals, at least one trunk for transmitting 7 the signalling signals, apparatus for connecting the 8 signal generating apparatus to the trunk, apparatus for 9 storing a plurality of program building blocks for commanding generation of the signalling signals according 11 to a plurality of protocols, apparatus for storing 12 designations of particular ones of the program building 13 blocks to command operation of the signal generating 14 apparatus in accordance with a particular predetermined lS protocol, apparatus for enabling the particular ones of 16 the program building blocks during the processing of a 17 call to or from another switching office, whereby 18 communication therewith in accordance with the particular 19 predetermined protocol is mandated.
While reference to the invention being 21 implemented on a switching office is made throughout this 22 specification, it should be noted that the invention can 23 be implemented on suitable PABXs, and therefore reference 24 to switching offices (switching systems) throughout this specification should be construed to include such PABXs.
26 The invention can be used equally in analog and digital 27 systems, and in types used to transmit analog voice, 28 digital (PCM) voice, or data signals.
29 A better understanding of the invention will be obtained by reference to the detailed description below, 31 with reference to the following drawings, in which:
32 Figure 1 is a block diagram of a switching 33 system utilizing the present invention, 34 Figure 2 is a block diagram of a signal processor peripheral interface circuit used as part of ~ 2009034 02 the invention, 03 Figure 3 is a block diagram of a digital 04 signal processor module used in the signal processor 05 of the invention, 06 Figure 4 is a first terminal screen form 07 used in an embodiment of the invention, and 08 Figure 5 is a second terminal screen form 09 used in an embodiment of the invention.
Refer now to Figure 1, which illustrates a 11 basic block diagram of a switching system such as one 12 sold by Mitel Corporation under the trade mark 13 GX5000~ implementing the present invention.
14 The switching system is formed of a main controller 1 to which memory 2 is connected, and a 16 main parallel bus 3 to which the main controller is 17 connected. A circuit switch 4 controlled by a 18 controller 5 which is connected to the bus 3, switches 19 pulse code modulated (PCM) signals via lines 6 to inputs of peripheral switches 7A-7N, to which 21 peripherals such as line circuits and trunk circuits 8 22 are connected. The controllers 1, 5 and 10 can be 23 implemented in a single controller. Peripheral 24 switches 7A-7N are controlled by peripheral controllers 8A-8N. Control signals from main 26 controller 1 are switched to controllers 8A-8N by 27 means of a message switch 9 which is controlled by 28 controller 10, connected to bus 3 for receiving 29 control messages from main controller 1. The switches are combination time and space division switches, as 31 described in U.S. Patent 4,510,597 issued 32 April 9th, 1985 assigned to Mitel Corporation and 33 entitled "TIME DIVISION SWITCHING MATRIX".
34 Programs to control operation of this system are stored in memory 2, and are accessed by 36 main controller 1.
37 In order to effect R2 inter-office 38 signalling, input-output (I/O) circuits such as 2 circuit 11 are connected to peripheral switch 7N. Each 3 I/O circuit 11 is connected to an I/0 bus 12, which is 4 connected to peripheral switch 7N. I/0 circuit 11 is

- 5 formed of a transmitter 13 and a receiver 14 for

6 respectively transmitting and receiving signalling

7 signals respectively to and from an inter-office trunk

8 15. The transmitter and receiver are controlled by

9 control logic 15A.
Another I/0 bus 16 is connected to peripheral 11 switch 7N. Communications may be made between different 12 peripherals via peripheral switch 7N, and via switch 7N, 13 switch 4, switch 7A and between peripherals connected to 14 the various peripheral switches 7A-7N. It should also be noted that message (control) signals may be applied to 16 any peripheral from controllers 8A-8N due to their 17 connection to peripheral switches 7A-7N internally.
18 Thus, for example, a message may be transmitted from main 19 controller 1 through bus 3, controller 10, message switch 20 9 to peripheral controller 8N. Controller 8N in response 21 can control control logic 15 through switch 7N, for 22 controlling either or both of transmitter 13 and receiver 23 14 connected to trunk 15.
24 A system similar to that described above is 25 described in more detail in the following patents: U.S.
26 Patent 4,510,597 issued April 9th, 1985 entitled "Time 27 Division Switching Matrix"; U.S. patent 4,615,028 issued 28 September 30th, 1986 entitled "Switching System with 29 Separate Supervisory Links: and U.S. Patent 4,685,102 30 issued August 4th, 1987 entitled "Switching System 31 Loopback Test Circuit", to which the reader is referred 32 for information.

33 As this form of switching system is under 34 stored program control, diagnostic and communication 35 with the system by a technician is made via a computer 36 terminal 17 which is connected to a bus interface 18 02 of conventional form, which itself is connected to the 03 main parallel bus 3.
04 In accordance with the present invention a 05 digital signal processor peripheral interface circuit 06 (SP PIC) 19 is connected to bus 16. Each SP PIC
07 occupies, in a successful prototype, one slot in a 08 peripheral switch rack-mounted shelf, and contains 09 eight signal processing modules 21, referenced DSP
module #0 - DSP module #7 in Figure 1. Each DSP
11 module is connected to the output of a multiplexer 22, 12 which interfaces the I/O bus 16 and to a 13 serial/interrupt controller 23. Controller 23 and the 14 DSP modules can be connected together and combined with MUX 22 by connecting the DSP modules 21 and 16 controller 23 to bus 16 via a switching matrix as 17 described in the aforenoted patents.
18 Figure 2 illustrates a more detailed block 19 diagram of the signal processor PIC. The peripheral bus 16 is connected to the input of multiplexer 22.
21 The output of multiplexer 22 is a serial PCM line PCS
22 IN which is connected to the input of serial/interrupt 23 controller 23. A serial message line DATA IN is 24 connected from the output of multiplexer 22 to serial/interrupt controller 23. In addition clock and 26 frame pulse signals are applied from the output of 27 multiplexer 22 to the input of controller 23. The 28 latter are also applied to corresponding inputs of 29 illustrated DSP module #0, 21.
Serial input lines SI0 and SIl are 31 connected from controller 23 to corresponding inputs 32 of DSP module 21, with control in CTRIN and clear 33 interrupt CLRINTR lines. Output serial lines from DSP
34 module 21 SO0, SOl and S02 are connected to controller 23, along with a TMSINTR line.
36 Output lines from controller 23 are serial 37 SPSC OUT and MPSC OUT, and serial data lines SDTA OUT
38 and MDTA OUT which are connected to bus 16, and thus 01 _ 9 _ 02 to peripheral switch 7N. SPSC IN and SPSC OUT are the 03 same plane PCM paths (i.e. they are connected to the 04 peripheral controller/matrix residing in the same 05 shelf). MPSC IN and MPSC OUT are connected to the 06 mate plane controller. SDATA OUT and MDATA OUT carry 07 message information via bus 16 to peripheral switch 7N.
08 The data in, C244, FP and clock lines are 09 connected to data bus 25 (see Figure 1). That bus is connected to another serial/interrupt controller 11 associated with DSP module #1. In this manner, 12 several DSP modules can be connected with an 13 associated controller to the serial output of 14 multiplexer 22.
Figure 3 illustrates a preferred form of 16 the DSP module. The module is controlled by a 17 controller 28, which preferably is formed of a 18 microprocessor such as Texas Instruments type 19 TMS32010. Connected to the controller 28 is a random access memory RAM 29 having 16K bytes. An ASIC 30 is 21 connected to RAM 29 and controller 28.
22 The structure of the ASIC should perform 23 the following functions: It should allow the 24 microprocessor 28 to be controlled via a serial bus link. It should support a host interface bound 26 interrupt from the controller 28. It should provide 27 an interface between the controller parallel bus and 28 the serial bus. It should support a host interface 29 controlled interrupt sequence for the controller 28.
This interrupt sequence should be synchronized to the 31 serial bus. It should contain a boot strap program 32 required to download applications program code from 33 the peripheral switch controller 8N into the memory 34 29. Finally, it should control the memory 29 page address bit.
36 The CTRLIN signal to the ASIC is a serial 37 link signal. Each channel on the link should contain 38 a command byte which is decoded and executed by the 02 DSP module. The ASIC executes the command byte during 03 the channel time which follows the channel on which 04 the command byte is received.
05 The serial/interrupt controller 23 is 06 implemented using an array of time division/space 07 division switches, such as described in U.S. Patent 08 4,510,597. Each of those devices provides a serial 09 control for a pair of DSP modules.
The system in general operates as 11 follows. Memories associated with controllers 8A-8N
12 each contain all building block program procedures for 13 implementing different portions of a variety of 14 inter-office trunk protocols for each possible signal to be transmitted. Memory 2 is partitioned to contain 16 in partitioned portion 32 a program of well known form 17 which allows data input charts to be displayed on the 18 screen of computer terminal 17, correlating received 19 signals versus functions to be performed.
Each of the DSP modules contain a 21 functionally simple non-customizeable program which 22 transmits and receives the MF-R2 signals, the 23 frequencies and levels of the tones thereof having 24 been specified in the CCITT standard.
After installation of the main switching 26 system and loading of the DSP modules, the customer 27 technician (operator) accesses main controller 1 by 28 terminal 17 through interface 18 and bus 3, which 29 brings from memory 32 a first chart on the screen of the terminal such as the one shown in Figure 4.
31 The operator defines the various 32 functional aspects using a predetermined set of user 33 codewords for each signal. Once all the aspects have 34 been defined, the main controller 1 downloads the user defined codewords to peripheral controller 8N
36 designating the particular program building blocks to 37 be used, for particular signals, where the correlation 38 is stored. The user defined codewords are downloaded ~ 2009034 02 by controller 1 through controller 10 and message 03 switch 9 to the peripheral switch controller 8N, where 04 the full complement of program building blocks are 05 stored, and resident in the control memories of 06 peripheral switches 7A-7N. The selected building 07 blocks then control the various switches and modules 08 to control the form of the signals output on the 09 various inter-office trunks, in accordance with the local variant of the R2 protocol.
11 In operation, controller 8N commands using 12 the designated correlated command that e.g. DSP module 13 21 should transmit a signal, by writing into channels 14 on the message link on bus 16 via peripheral switch 7N. A link is set up via switch 7N to a trunk 15.
16 From bus 16, the command is routed along the SDATAIN
17 or MDATAIN leads through MUX 22 and serial/interrupt 18 controller 23 into the DSP module on lead S10 where it 19 is read by the DSP program which is running there. A
resulting tone signal in PCM is generated which is 21 passed via bus 16 through switch 7N to bus 12 and is 22 transmitted via transmitter 13 to trunk 15.
23 Controller 8N is notified that a response 24 tone has been detected or received, by the DSP module writing into channels on the SO0 lead which are via 26 serial/interrupt controller 23 to the SDATAOUT and 27 MDATAOUT leads on bus 16.
28 It should be noted that once the PCM
29 connection is set up between the trunk 15 and a DSP
module via a switch 7N, MF-R2 signalling takes place 31 in-band. That is, the trunk control logic 15 does not 32 interact with the R2 protocol. At this point, the 33 trunk card is just carrying what it considers to be 34 speech (MF-R2 signals) and so the transmitter 13 and receiver 14 just perform normal digital-to-analog and 36 analog-to-digital conversions.
37 As an example, consider an outgoing trunk 38 call using MF-R2 signalling. A seize message is sent 02 from main controller 1, via message switch 9 to 03 peripheral controller 8N requesting it to cause 04 control logic 15 to seize trunk 15. Similarly, a 05 seize message is sent from main controller 1 to 06 peripheral controller 8N requesting it to schedule the 07 R2 register control program which is resident in its 08 memory. A PCM connection is set up from the DSP
09 module 21 to the trunk's transmitter 13 via peripheral switch 7N, circuit switch 4 and peripheral switch 7N.
11 Similarly a connection is set up via the same 12 switching matrices between the trunk's receiver 14 and 13 the DSP module 21.
14 The R2 register control program running on peripheral controller 8N now causes DSP module 21 to 16 transmit the first forward signal as specified by the 17 downloaded codewords. It does this by sending a 18 message via bus 16 to DSP module 21 (as described 19 above).
When a response signal is received from 21 the far end trunk by DSP module 21, it notifies the R2 22 register control program resident at peripheral 23 controller 8N by sending a message via bus 16. Upon 24 receiving this message, the R2 register control program determines a signal to send in response using 26 the downloaded codewords and the sequence described 27 above is repeated.
28 This process continues until the protocol 29 is completed. At this time, the PCM connections to the DSP module are broken and MF-R2 signalling is 31 complete.
32 Figure 4 illustrates a form that can be 33 used on the terminal 17 as an aid for the customer 34 technician to characterize the signalling for one category of signals used in the protocol. In the 36 left-hand column are numbers of the fifteen different 37 signals, put up on the terminal 17 screen by 38 controller l, and in the second and third columns, the ~Q~34 02 action to be performed is entered by a technician 03 using predefined terms. Successive ones of the data 04 entry form are used for each category of signals in 05 the protocol. This form is definable only at the 06 installer level, i.e. the highest access authorization 07 level.
08 In the second and third columns, up to two 09 action responses can be entered. If both are specified, the first is executed before the second.
11 Of course the two procedures cannot be the same. The 12 system action responses can be selected from building 13 block procedures described below.
14 At the top of the form, it is entered whether the form is being used for incoming or 16 outgoing signals.
17 In the list of program building blocks 18 listed below, each action is defined by a first word 19 forming the language, followed by the function to be implemented by the system in response.

-- 20~034 Outgo1ng State Bu11d1ng Blocks Procedures wh1ch can be executed 1n the context of an outgo1ng R2 reg1ster are 11sted below. If the procedure m1ght be executed 1n response to a standard CCITT s1gnal, that s1gnal 1s 11sted bes1de the procedure.

CCITT Name of Procedure Standard / Descr1pt1on --- connect Release the MF-R2 transce1ver and connect the speech path. Set up the appropr1ate charg1ng mechan1sm 1f requ1red.
A-4,15 excep_congest1on B-4 Set the R2 except1on to congest1on.
B-8 excep dn out of serv Set the R2 except10n to DN out of servlce.
--- excep 1nval1d s1gnal Set the R2 except1on to 1nval1d s1gnal.
--- excep_none Set the R2 except10n to none (default).
B-3 excep_sub_busy Set the R2 except10n to busy.
B-5 excep_unass1gned_num Set the R2 except10n to unass1gned number.
--- excep user 1 Set the R2 except1on to user-def1ned except1on number 1.
--- excep user 2 Set the R2 except1on to user-def1ned except1on number 2.
--- excep user 3 Set the R2 except10n to user-def1ned except1on number 3.
--- reroute Term1nate the current call and attempt alternat1ve rerout1ng.

2~Q~034 . .

CCITT Name of Procedure Standard / Descr1pt10n --- reset CLI 1ndex Set the next CLI d1g1t 1ndex to the beg1nn1ng of the CLI number.
--- reset d1g1t 1ndex Set the next d1g1t 1ndex to the beg1nn1ng of the number.
A-3 send category A-5 Send category of call1ng party. Th1s procedure sends the category programmed 1n the class of serv1ce, us1ng the mapp1ng g1ven 1n the R2 Var1ant Ass 1 gnment.
--- send_f1rst_CLI_d1g1t Send the f1rst call1ng 11ne 1dent1f1ca-t1cn d1g1t. If no CLI 1s ava11able, the except10n handl1ng spec1f1ed 1n the R2 Var1ant Ass1gnment 1s used.
--- send f1rst_d1g1t Restart.
A-2 send last but 1 Send d1g1t (n-1).
A-7 send last but 2 Send d1g1t (n-2).
A-8 send last_but_3 - Send d1g1t (n-3).
--- send last_d1g1t Repeat last d1g1t sent (n).
--- send next CLI_d1g1t Send the next CLI d1g1t. If no more CLI
dlg1ts are avallable, the except10n handl1ng spec1f1ed 1n the R2 Var1ant Ass1gnment 1s used.
A-1 send next_d1g1t Send d1g1t (n+1).

-CCITT Name of Procedure Standard / Descr1pt1on --- set called control Mark the call as be1ng under called party control.
--- set_call1ng_control Mark the call as be1ng under call1ng party control.
A-6 set_chargeable B-6 Mark that the call 1s chargeable. Th1s 1s the default cond1t1on for every new call.
--- set_f1rst_control Mark the call as be1ng under f1rst party control.
--- set 301nt control Mark the call as be1ng under 301nt party control.
B-7 set_not_chargeable Mark that the call 1s not chargeable.
--- term1nate Release the MF-R2 transce1ver and term1nate the current call w1th except10n handl1ng spec1f1ed by the current R2 exceptlon.
--- send_1, send_2, send_3, send_4, send_5, send 6, send 7, send 8, send 9, send 10 send_11, send_12, send_13, send_14, send_15 Send the nth forward s1gnal.

Ol - 17 -Incom1ng State 8ulld1ng Blocks CCITT Name of Procedure Standard / Descr1pt1on --- cstegory ccb Mark the caller as a co1n collect1ng box.
II-6 category data Mark the caller as a data transm1ss10n.
II-5 category_operator Mark the caller as an operator.
II-1 category_ord1nary Mark the caller as an ord1nary subscr1ber.
II-2 category_pr1or1ty Mark the caller as a subscr1ber w1th pr10r1ty.
II-3 category test Mark the caller as test equ1pment.
--- excep 1nval1d_s1gnal --- excep_none See outgo1ng state bu11d1ng blocks.
I-10 process d1g1t 0 I-1 process d1glt_1 I-2 process d1g1t 2 I-3 process d1g1t 3 I-4 process d1g1t 4 I-5 process d1g1t 5 I-6 process d1g1t_6 I-7 process d1g1t 7 I-8 process_d1g1t 8 I-9 process d1g1t 9 I-15 process d1g1t t1meout Use the spec1f1ed d1g1t, rhe d1g1t tree and the 1nformat10n 1n the R2 Var1ant Ass1gnment to attempt to route the call.
--- send status and end Send the called party status. When the s1gnall1ng cycle 1s complete, e1ther clear down the call or connect the speech path.
--- term1nate See outgoing state bu1ld1ng blocks.
--- send 1, send 2, send 3, send 4, send 5, send_6, send 7, send_8, send_9, send 10, send_11, send_12, send_13, send_14, send_15 Send the nth backward s1gnal.

02 It should be noted that the particular 03 procedures specified are all procedures that are 04 normally implemented in a switching office.
05 Consequently the particular program listings are not 06 given herein, as they will be different for each form 07 of switching office and are known to persons skilled 08 in the art.
09 A representative second form which is preferred to be used to define variants, that is, to 11 specify the initial procedures and conditions and time 12 outs, as well as parameters for the program building 13 block procedures, such as the mapping of logical 14 conditions to physical signals, is shown in Figure 5.
A list and description of each of the 16 fields to be identified follows:

2~034 g 01 -- 19 -F1eld De~cr1pt10ns 1. In1t1al outgo1ng procedure The 1n1t1al outgo1ng procedure 1s the R2 bu1ld1ng block procedure wh1ch should be executed when outgo1ng R2 s1gnall1ng 1s 1n1t1ated. Th1s procedure 1s generslly send f1rst d1g1t, but 1 n some cases the expl1c1t s1gnal procedures (send1, send2 etc.) may also be useful.

2. In1t1al outgo1ng state The 1n1t1al outgo1ng state 1s the state to enter after execut1ng the 1n1t1al outgo1ng procedure. The reg1ster stays 1n th1s state unt11 1t e1ther rece1ves a back~ard s1gnal from the 1ncom1ng reg1ster or the forward tone t1meout per10d exp1res. When th1s form 1s comm1tted, the remsrk programmed aga1nst the requested state 1s d1splayed 1n a protected f1eld.

3. CalllnD party category The data 1n th1s sect10n are used to map the call1ng party category (as dof1ned 1n the class of serv1ce) to a phys1cal R2 s1gnal to transmlt when the calllng party category 1s requested.

4. Except10n handl1ng The s1gnals 1n th1s sect10n are used to respond to backward s1gnalled requests wh1ch the outgo1ng R2 reg1ster cannot comply w1th.

(a) CLI not ava1lable Th1s def1nes the s1gnal to return 1f a request for call.-~g 11ne 1dent1f1cat10n d1g1ts has been rece1ved, but none are ava1lable (for example, on a tandem call when the-1ncom1ng 11nk does not transm1t the call1ng party's number). If no s1gnal 1s spec1f1ed, none 1s returned. If no next state 1s spec1f1ed, execut10n cont1nues 1n the same state.
When th1s form 1s comm1tted, the remark programmed aga1nst the requested state 1s d1splayed 1n a protected f1eld.

Th1s except10n handl1ng 1s 1nvoked by the send_f1rst_CLI_d1g1t procedure.

2009~34 -(b) No more CLI d1g1ts - Thls def1nes the slgnal to return 1f a request for more CLI d1glts (not 1nclud1ng the f1rst) has been rece1ved, but none are ~va11able If no s1gnal 1s speclf1ed, none ls returned. If no next state 1s speclf1ed, execut10n cont1nues 1n the sane state.
When th1s form 1s comm1tted, the re~ark programmed aga1nst the requested state 1s d1splayed 1n a protected f1eld.
Thls exceptlon handl1ng ls lnvoked by the send_next CLI_dlglt procedure.

(c) No more d1g1ts Thls deflnes tho s1gnal to return lf a request for more d1g1ts (not 1ncludlng CLI d1g1ts) has been rece1ved, but none are avallable. If no slgnal ls speclfled, none ls returned. If no next state ls speclfled, executlon contlnues ln the same state.
When thls form .18 com~ltted, the remark programmed agalnst the requested state ls d1splayed 1n a protected fleld.
Th1s handl1ng ls 1nvoked by the send_next_dlglt ~rGccJure when call processlng determlnes that the entlre called number has been entered and the term1nat1ng re~1ster requests another d1g1t. The ent1re called number 1s cons1dered entered when er1tlcal t1m1ng has been completed or the last d1g1t 1n the dlg1ts to follow programmed agalnst the route has been recelved.

5. Forward tone t1meout The forward tone tlmeout 1s the maxlmum per10d for whlCh the outgo1ng reg1ster w111 cont1nue to transmlt a forward s1gnal 1n the absence of an acknowledg1ng backward s1gnal. It 1s also the max1mum per10d for whlch the outgo1ng reg1ster wlll wa1t for a pulsed bsckward s1gnal when no forward s1gnal 1s belng sent.
If thls t1meout occurs, the call wlll be ternlnated.
CC~TT ~.476 res: ~nd6 a perlod of 15 l/- 3 seconds.

6. No-tone t1meout The no-tone t1meout ls the maxlmum perlod for whlch - the outgo1ng reg1ster w111 walt for a backward s1gnal 200~034 to be r.---vod after the t1me that the forward slgnal 18 romoved. If th1s t1meout occurs, tho call w111 be term1nated.

7. In1t1al lncomlng stato The lnltlal lncomlng state ls the state wh1ch the 1ncom1ng reg1ster enters when 1t 1s f1rst seized.
When th1s form 1s comm1tted, the remark programmed agalnst the requested state 1s d1splayed 1n a protected f1eld.

8. Called party status s1gnals The data 1n th1s sect10n are used by the 1ncoming reg1ster to map the called party status (as detérmlned by call procasslng) to a phys1cal R2 s1gnal to send when the called party status 1s to be transm1tted. Moro than ono ststus may be ~Fe~ to the same physlcal slgnal. For example, lf spec1al 1nformat10n tone 1s ava1lable, access v101at10ns m1~ht be r~p~~ to the s1gnal to request 1t. If 1t ls not avallablo, acce6s vlolat10ns m1~ht be ,~p~d to tho same slgnal as dlrectory numbor out of servlce.

9. D1g1t process1ng act1on table Thls table maps the d1gtt processlng actlons wh1ch m1ght be requ1red to route a call to the phys1cal R2 s1gnJls to transm1t 1n order to request these actlons. For example, lf the dlg1t tree 1nd1cates that another dlglt ls requlred, the 'Send next d1g1t' slgnal ls sent.
If no slgnal ls programmed aga1nst an act10n, call processlng wlll use the rules speclfled 1n Sect10n 2.1 under D1g1t Process1ng Act10n Table.
At least one of the two 'address done' cond1t10ns must be programmed. When th1s form 1s comm1tted w1th a next state programmed for the 'address complete, get category' f1eld, the remark programmed aga1nst that state 1s d1splayed 1n a protected f1eld.

10. Delay before start1ng pulsed s1gnal Th1s delay 1s 1nserted between the end of transm1ss10n of the last s1gnal of the compelled cycle and the start of transm1ss10n of the pulsed s1gnal. It must be spec1f1ed 1n 1ncr~ -nts of 30 ms.
CCITT 0.442 re~c -nds a m1n1mum delay of 100 ms.

- 200~34 ,

11. Pulsed slgnal dura~1on Thls f1eld spec1f1es the durat10n of s1gnals sent as pulsed s1gnals. It must be speclf1ed 1n 1ncrements of 30 ms. CCITT ~.~42 r~Gco. =nds a pulsed s1gnal durat1on of 150 ms.

12. Pulsed s1gnal rece1ver r~connect delay Th1s f1eld spec1f1es the t1me, after the complet10n of the pulsed backward s1gnal, before the 1ncom1ng rece1ver can be reconnected. It 1s 1gnored 1n cases where the R2 reg1ster s1gnall1ng 1s term1nated after send1ng the pulsed s1gnal. Th1s delay must be spec1f1ed ln 1llcrerents of 30 ms. CCITT 0.442 rec-- -nds a delay of 300 +/- 100 ms.

13. Pulsed return s1gnal for f1rst/inter-d1g1t t1mer explry If the f1rst d1g1t or 1nterd1g1t t1mers, as programmed on a trunk's class of serv1ce, exp1re, thls fleld deflnes the slgnal wh1ch should be return-d, 1n pulsed form, before the call 1S
term1nated. If no slgnal lS speclfled, none ls sent.

2Q~9034 02 The following illustrate filled in action 03 identifying forms for six separate signalling 04 conditions, in which the first represents a state of 05 sending outgoing digits, the second of sending 06 outgoing CLI, the third of handling the receipt of the 07 called party status after confirmation the outgoing 08 category has been sent, the fourth of receiving 09 incoming digits, the fifth of terminating signalling after sending signal BJ, and the sixth of handling the 11 receipt of the calling party category and terminating 12 signalling after sending the called party status. The 13 assignment noted has been created to cause performance

14 of the R2 signalling variations of Kenya, for a switching system manufactured by Mitel Corporation 16 designated by the trade mark GX5000. The various 17 signal functions identified above are noted in the 18 headnote of each form. The procedures listed 19 correspond to the building block functions described earlier in this disclosure.

-R2 Signal State Assignment R2 Var1ant : 1 R2 State : 1 Re~arks : A_Send Dgts Type (Inconlng/Outgolng) : Outgoing Sl~nal Responso to S1~nslN~xt State Reco1ved F1rst procoduroSocond proceJuro No. Re~arks ////1/// send next d1g1t /////////////
////2/// send_last_but_l /////////////
////3/// send category 3 /B Sent Catgy ////A//~ excep congest10n reroute //7////7/////
////5/// send categoryreset CLI 1ndex 2 /A Send CLI//
////6/// set chargeable connéct //7////7/////
////7/// send last but 2 /////////////
////8//~ send lsst but 3 /~///////////
////9/// send_f1rst_d1g1t ~ /////////////
///lD/// set chsrgeable connect ~ /////////////
///11/// sot ch~rgeable connoct /////////////
///12/// set chargesble conn~ct /////////////
///13/// set chsrgesble connect /////////////
///14/// sot chargo~blo connoct /~///////////
///15/// set_chargeable connect /////////////
~ .

- 200qo34 R2 Signal State Assignmënt R2 Varlant : 1 R2 State : 2 Remarks : A Send_CLI
Type (Incom1ng/Outgo1ng) : Outgo1ng S1gnalResponse to S1gnal .Next State Rece1ved F1rst procedure Second procedure No. Remarks ////1/// excep unsss1gned num term1nate /////////////
////2/// excep unasslgned num termlnate ~////////////
////3/// excep_unass1gned num termlnate /////////////
////4/// excep_con~st1on reroute /////////////
////S/// send_next_CL~_dlglt . /////////////
////6/// excep_unass1gned_num term1nate /////////////
////7/// excep unass1gned num term1nate /////////////
////8/// excep unass1gned_num term1nate /////////////
////9/// excep unass1gned num term1nate /////////////
///10/// excep unass1gned nu~ term1nate /////////////
///11/// excep_unass1gned_num term1nate' /////////////
///12/// excep_unass1gned_num term1nate //////t//////
///13/// excep unass1gned num term1nate /////////////
///14/// exc-p unass1gned num term1nate /////////////
///15/// excep_unass1gnod_num t-rm1nate /////////////

R2 Signal. Sta~e~ ~signment R2 Var1ant : 1 R2 State : 3 Remarks : B Sent Catgy Type (Incom1ng/Outgo1ng) : Outgo1ng S1gnal Res~onsa to 51gnal Next State Rece1ved F1rst procedure Second procedureNo. Remarks.
////1/// excep_unass1gned num term1nate . j//////~/////
////2/// excep unass1gned num term1nate /////////////
////3/// excep sub busy t'~rm1nate /////////////
////4/// excep congest10n reroute ////////~////
////5/// excep unass1gned num term1nate ////////~////
////6/// set chargeable connect /////////////
////7/// excep unsss1gned num term1nate /////////////
////8/// excep_unass1gned_num term1nate /////////////
////9/// excep unass1gned num term1nate - /////////////
///10/// excep unass1gned num term1nate /////////////
///11/// excep_unass1gned_num term1nate /////////////
///12/// excep unass1gned_num term1nate /////////////
-///13/// excep unass1gned num term1nate . /////////////
///14/// excep unass1gned num term1nate /////////////
; ///15/// excep_unass1gned_num term1nate /////////////

Ol - 26 - 2~034 R2 Var1ant : 1 R2 State : 4 Remarks : I_Rcv D1g1ts Type (Inco~1ng/Outgolng) : Inco~1ng S1~nal Response to S1gnalNext State Recelved F1rst procedure Second procedureNo. Re~arks ////1/// process dlglt /////////////
////2/// process dlglt /////////////
////3/// process d1g1t /////////////
////4/// process_d1g1t /////////////
////5/// process d1g1t /////////////
////6/// process d1g1t ./////////////
////7/// process d1g1t /////////////
////8/// process d1g1t /////////////
////9/// process_d1g1t /////////////
///10/// process d1g1t /////////////
///11/// send3 5 /B5 Next/////
///12/// sond3 5 /B5_Next/////
///13/// send3 5 /B5_Next/////
///14/// s-nd3 5 /B5_Next/////
///15~// send3 5 /B5_Next///~/

R2 Var1ant : 1 R2 State : 5 Remarks : B5_Next Type (Incom1ng/Outgo1ng) : Incom1ng S1gnal Response to S1gnalNext State Rece1ved F1rst procedure Second procedure No. Remarks ////1/// send5 term1nate/////////////
////2/// send5 . term1nate/////////////
////3/// send5 term1nate/////////////
////4/// send5 term1nate/////////////
////5/// send5 term1nate/////////////
////6/// send5 ' term1nate /////////////
////7/// sendS term1nate /////////////
//~/8/// send5 term1nate /////////////
////9/// send5 term1nate /////////////
///10/// send5 term1nate /////////////
///11/// send5 term1nate /////////////
///12/// send5 term1nate /////////////
///13/// send5 term1nate /////////////
///14/// sendS term1nate /////////////
///15/// sendS term1nate /////////////

05 R2 Var1ant : 1R2 Stato : 6 Renarks : II_Catgy_Nxt Type (Inconlng/Outgo1ng) : Ine.~m~ng 07 S1 gnalResponse to Slgnal Next State 08 Rece1ved F1rst procedure Second procedure No. Re~arks 09 ////1/// category ord1nary connect reply status /////////////
////2/// category_ord1nary connect_reply_status /////////////
lO ////3/// category_ord1nary connect_reply_status /////////////
////4/// category_ord1nary conntct reply_status ///////~/////
11 ////5/// category ord1nary connec~ reply status /////////////
////6/// category ord1nary conn~ct reply status /////////////
12 ////7/// category ord1nary conncct reply status /////////////
////8/// category ord1nary connect reply status /////////////
13 ////9/// category ord1nary connl~ct reply status /////////////
14 ///10/// category ord1nary connect_reply_status /////////////
///11/// category ord1nary connect_reply_status /////////////

15 ///12/// category ord1nary connect reply status /////////////
///13/// category ord1nary connect_reply status /////////////

16 ///14/// category_ord1nary connect reply_status /////////////

17 ///15/// category ord1nary connect_reply_status /////////////

18

19

20 The associated variant assignment is shown

21 below.

22 ~ Q~034 R2 Var1ant : 1 OUTGOING REGISTER PARAMETERS
In1tlal outgolng procedure : send f1rst dlg1t In1tlal outgolng state . . : 1 Remarks : A Send Dgts/
Call1ng Party Category 51gnals (1-15) Co1n collect1ng box. . . . :
Data transmlssion. . . . . :
Operator trunk . . . . . . : 1 Ord1nary subscr1ber. . . . : 1 Subscr1ber w~th pr1or~ty . :
Test equ1pment . . . . . . :
Except1on Handllng CLI not avallable (1-15) . : 15 Next state : 1 Remarks : A Send Dgts/
No more CLI dlglts (1-15). : 15 Next state : 1 Remarks : A Send Dgts/
No more dlglts (1-15). . . : Next state : Remarks : /7~///7/////
Outgo1ng Tone-On T1meout (1-60 seconds) . . : 15 Outgo1ng Tone-Off T1meout (1-60 seconds). . : 30 INCOMING REGISTER PARAMETERS
Inltlal lncomlng state : 4 Remarks : I Rcv Dlglts Dlglt Processlng Request Slgnals (1-15) Send next dlg1t. . . . . . : 1 Send flrst dlglt . . . . . : 9 Send last dlg1t. . . . . . :
Send last but 1. . . . . . : 2 Send last but 2. . . . . . : 7 Send last but 3. . . . . . : 8 Dlglt Processlng Complete Handllng Calle~ party status transfer ~echanlsm (CCITT, I~medlate, None) : CCITT
Charge/setup speech (1-15) : 6 Congestlon/no swltch (1-15): 4 Get caller category (1-15) : 3 Next state : 6 Remarks : II Catgy_Nxt Called Party Status Slgnals (1-15) Access v101at10n . . . . . : 5 Busy . . . . . . . . . . . : 3 Congest1on . . . . . . . . : 4 DID trunk congestlon . . . : 3 DN ln a parked state . . . : 3 DN out of servlce. . . . . : 5 Free, charge . . . . . . . : 6 Free, no charge. . . . . . : 6 Routed to lntercept or RAD : 6 Unasslaned number. . . . . :
User-deflned exceptlon 1 . : 4 User-deflned except10n 2 . : 4 User-def1ned exceptlon 3 . : 4 Delsy before startlng pulsed slgnal (60-240 ms, 30 ms steps). . : 150 Pulsed si~nal durat~on (90-900 ~S, 30 ~S steps) , . . , , . . . : 150 Pulsed s1gnal recelver reconnect delay (90-900 ms, 30 ms steps) : 300 Pulsed return s1gnal for f1rst/lnter-s1gnal tlmer explry (1-15) : 4 02 It may thus be seen that with the 03 embodiment described above the customer can cause the 04 switching office to identify the building block 05 programs from the large number of available programs 06 stored in the peripheral controller memories. The 07 result is that controlling programs selected out of a 08 large number of available programs cause the system to 09 self configure so as to process inter-office signalling according to the particular local variant.
11 ThiS is done without requiring special attention by 12 the system manufacturer, and can be changed at will by 13 the customer to accommodate a change in location of 14 the switching office, to update the protocol and upon installation.
16 While the embodiments described refer to 17 R2 signalling, the principles of this invention are 18 not limited for use with R2 signalling, or indeed to 19 inter-office signalling, and may be applied for self-configuration of the switching system in order to 21 adapt it to any other local conditions desired.
22 A person skilled in the art understanding

23 the present invention may now conceive of variations

24 or other embodiments using the concepts described herein. All are considered to be within the sphere 26 and scope of the invention as defined in the claims 27 appended hereto.

Claims (20)

We claim:

1. A method of producing interoffice signalling comprising:
(a) storing program building blocks for commanding generation, in a plurality of signalling protocols, of signalling signals in a communication switching system, (b) storing correlations of particular ones of said program building blocks with a particular protocol for signalling functions related to the process of a call to or from said communication switching system, (c) enabling operation of said particular ones of said program building blocks when a particular signalling signal is to be generated in the processing of a telephone call to or from the communication switching system, to match said particular protocol, whereby the communication switching system is enabled to process calls restricted to said particular protocol out of said plurality of protocols for a particular call.

2. A method as defined in claim 1, including generating the signalling signals in a universal signalling generator which is adapted to receive commands from the program building blocks and to generate signalling signals in response thereto.

3. A method as defined in claim 1, including connecting the universal signalling generator to a trunk through a switch, and transmitting the signalling signals to the trunk via the switch for transmission to a remote communication switching office.

4. A method as defined in claim 3, including transmitting the signalling signals in a voiceband to the remote telephone switching office.

5. A method of interoffice signalling of a communication switching system comprising:
(a) storing program building blocks for commanding operation, in a plurality of signalling protocols, of a signalling signal generator and signalling signal receiver;
(b) storing designation of particular ones of said program building blocks which relate to a particular signalling protocol to be used by said system;
(c) enabling operation of only said particular ones of said program building blocks during the processing of a call to or from said system, to command the signal generator to generate particular signals to be generated or to detect the receipt of particular signals received by said receiver, whereby the communication switching system is enabled to process calls restricted to said particular protocol out of said plurality of protocols.

6. A method as defined in claim 5, including the steps of displaying a chart of signalling functions, receiving command data from an operator relating to particular signalling operations to be used by the system corresponding to said functions, and processing the command data to form said program building block designations.

7. A method as defined in claim 6 including providing a signal generator and signal receiver which can respectively transmit and receive signalling signals in forms corresponding to all said plurality of signalling signals, the signalling generator operating in response to said command data to generate signals only in accordance with said particular protocol.

8. A method as defined in claim 7 including connecting the signal generator and signal receiver to a trunk for transmitting and receiving signals via said trunk.

9. A method as defined in claim 8 in which the signalling signals are transmitted and received in voiceband via said trunk.

10. A method as defined in claim 8 in which said signals are pulse code modulated.

11. A communication switching system comprising:
(a) signal generating means for generating interoffice signalling signals, (b) at least one trunk for transmitting the signaling signals, (c) means for connecting the signal generating means to the trunk, (d) means for storing a plurality of program building blocks for commanding generation of the signalling signals according to a plurality of protocols, (e) means for storing designations of particular ones of the program building blocks to command operation of the signal generating means in accordance with a particular predetermined protocol, (f) means for enabling said particular ones of the program building blocks during the processing of a call to or from another switching office, whereby communication therewith in accordance with said particular predetermined protocol is mandated.

12. A system as defined in claim 11, in which the means for storing said program building blocks and means for storing said designations is a peripheral processor memory adapted to transmit said particular ones of the program building blocks to the signal generating means.

13. A system as defined in claim 12, in which the means for connecting the signal generating means to the trunk is a switch controlled by the peripheral processor.

14. A system as defined in claim 11 in which the signal generating means is comprised of a controller for receiving said particular ones of the program blocks and a signal generator controlled by the controller for generating said signals.

15. A system as defined in claim 14 in which said signal generating means includes a receiver for receiving signals from said another switching office, controlled by the controller.

16. A system as defined in claim 15 in which the means for connecting the generating means to the trunk is a time and/or space division switching matrix.

17. A system as defined in claim 16, in which the means for storing said program building blocks and means for storing said designations is a peripheral processor memory adapted to transmit said particular ones of the program building blocks to the signal generating means.

18. A system as defined in claim 17, in which the switching matrix is controlled by the peripheral processor.

19. A system as defined in one of claims 11-14 including a system processor for controlling operation of said system and for generating a display, means for receiving data relating to signalling functions for predetermining said protocol in response to said display, means for generating said designations of particular ones of the program building blocks, and for providing said designations to said means for storing said designations.

20. A system as defined in one of claims 11-14 including an operator input-output console, a system processor controlling operation of said system and console, means for generating a display on said console relating to signalling functions, means for receiving data input on the console relating to particular signals for predetermining said protocol in response to said display, the system processor including means for generating designations of particular ones of the program blocks corresponding to said data, and for providing said designations to said means for storing said designations.